1. Field of the Invention
The present invention relates to a dot printer for printing characters, halftone images and the like with small pixels (dots).
2. Description of the Prior Art
Various recording element sections or printer heads for use in dot printers that form output images with dots are known. Examples of such heads include a wire dot printer head, an electrostatic printer head, an ink-jet printer head, a thermal printer head, an LED (light emitting diode) array printer head and the like. An LED array printer head having 8 or more elements per mm as the dot generating elements is receiving considerable attention due to its extremely high resolution. When this head is used in place of an optical scanning mechanism in a conventional electrophotographic copying machine, a printer can be realized in which an array of LED's is selectively turned on in accordance with a video signal to form an electrostatic latent image on a surface of an adjacent photosensitive body and a visualized image is obtained through a transfer process of the developed image onto a transfer sheet. In a printer of this type, a portion corresponding to the "ON" LED's can be formed into a black or white image portion by changing the charging conditions or toner.
In U.S. Pat. No. 4,596,995, examples of printers of the kind referred to above are described. In printers described in this apparatus, registers are provided for latching image data signals to respective LED's or recording elements to be enabled. In order to determine which register is to latch an image data signal rather complex circuitry in the form of a counter and decoder is provided to generate a signal to allow a register to latch the data from a data bus.
It is an object of the invention to provide printer apparatus with a more simplified means for data latching and that is particularly advantageous when multiple bits of data are used to record each pixel or dot.
It is a further object of the invention to provide printer apparatus with a data latching means that allows for similar circuitry for data latching to be operated in selected directions, the advantages of which will be more fully appreciated after reading of the specification herein.